Previously known light signs of the above mentioned kind are provided with an internal, disc-shaped holder to which the discharge tube is fixed by means of clamps. This attachment is work requiring and the handling of the discharge tubes involves damaging risks both for the material and the mounting staff. The transparent panel must be attached with relatively large space to the holder disc in order to be tolerably regularly illuminated by the discharge tube and not to get a striped appearance. In that way the thickness of the sign becomes considerable, and the body of the sign as well as the supporting construction must be performed with a corresponding larger dimensions, which results not only in aesthetic but also in great practical disadvantages.
According to the other known devices (GB-B No. 465,135, U.S. Pat. Nos. 1,961,735, 2,095,291, 2,080,679) the discharge tubes are placed in casted, milled or in other ways made grooves in a two part plate, where the grooves and the discharge tubes have been given the desired configuration, e.g. the shape of one or several letters, which means that the sign picture is determined by the shape of the groove, or where the discharge tube and the groove have been given a meander-shape and the sign picture is located as a separate unit in front of and/or behind the discharge tube. bending the discharge tubes in grooves made in a transparent material or vice versa is a circumstantial and expensive manufacturing method. Besides the tubes need space for thermic expansion at the same time as they should be effectively fixed in the grooves, which also causes complications. Light signs consisting of corrugated, transparent panels are known through U.S. Pat. No. 3,300,885. In the wave trough of the panel an U-formed discharge tube is fitted. Two similar panels are located on each other and are held removably together by a frame, forming a plurality of channels, through which the crests of the waves are located to fit-up against each other.
This type of light sign does not have any possibility of replaceable sign panels and if any operation must be done on the sign e.g. changing of a discharge tube, the whole sign with the frame must be dismounted.
The object of the invention is to provide a light sign especially intended to be used in such connections, where a resigning often occurs, e.g. en taxi-cabs and where the sign should be very narrow for having a as little air resistance as possible, where the resigning should be done with a few maipulations and without weakening the frame construction of the sign. The light sign should further by simple means be connectible to attachments of different kinds, so that several light signs can be joined to each other forming a continuous unit e.g. for providing of screen walls for exhibition purposes. These objects have been achieved by the features given in the claims.